PRECONCENTRATION AND REMOVAL OF TRACE-METALS FROM WATER BY APPLE WASTE

The control of trace metals in waters for analytical purposes or for their removal, usually requires a preconcentration technique. Preconcentration by the binding of dissolved trace metal ions onto a solid support is a widely employed technique. Agricultural waste from the elaboration of cider has been used as an alternative and cheap polymeric support with suitable properties for collecting heavy metal ions in very low concentrations due to the presence of acidic groups (carboxylic and phenolic groups). The residues have also been chemically modified by treatment with phosphorus(V) oxychloride in order to improve their physico-chemical characteristics. Small packed beds filled with apple residues have been used to preconcentrate heavy metal traces from synthetic solutions and from seawater; the influence of the pH and the flow rate being studied. The sorbed metals were eluted with HCl and subsequently analysed by atomic absorption spectrophotometry. A synthetic cationic resin, Amberlite IR-120, was also employed when preconcentrating heavy metal traces from seawater in order to compare the results.